BRAINCAKEThe Lungs
The lungs are a pair of structures made up of branched tubules called bronchioles which end in tiny air sacs called alveoli
The trachea is a flexible tube that leads to the buccal(mouth) and nasal cavities through which air can flow to and from the external environment.
It is supported by C-rings or incomplete rings of cartilage. The walls are made up smooth muscle lined with ciliated epithelial cells and goblet cells. Goblet cells secrete mucus which traps bacteria and dust particles.
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Key terms in this lesson
- alveolus
- A tiny, thin-walled air sac in the lungs, surrounded by capillaries, that is the site of gas exchange.
More in Exchange of Gases
- Stomata
- Limiting Water Loss in Insects
- Limiting Water Loss in Plants
- The Human Gas Exchange System
- Mechanism of Breathing
- Inspiration
- Expiration
- Alveoli
All 28 lessons in Exchange of Gases · All AQA AS-level Biology topics